Photojournalist Gary Braasch dies on Great Barrier Reef

A celebrated American photojournalist has died while documenting the impact of climate change on the Great Barrier Reef, the Australian Museum said on Monday.

Veteran nature photographer and environmental campaigner Gary Braasch, from the north-west US city of Portland, Oregon, was snorkeling with a companion near Lizard Island, about 270 kilometres north-east of Cairns, when he was found floating face down in the water on Monday morning.

The Australian Museum said Mr Braasch had been temporarily based at the station while photographing the reef to document the impact of climate change.

Mr Braasch was an award-winning nature photographer who had spent 40 years travelling the world taking pictures.

According to his website, braaschphotography.com, his work has been published by celebrated US publications such as the New York Times Magazine, Life, Time, National Geographic, Smithsonian, and the United Nations among many others.

Environmental photographer Gary Braasch.

Photo: Supplied

According to his website, Mr Braasch's central focus since 2000 had been climate change and global warming.

His photographic essay, Earth Under Fire: How Global Warming is Changing the World was published in 2007 and updated in 2009.

Environmental photographer Gary Braasch.

Photo: Supplied

"Gary was the first photojournalist who journeyed extensively, including to China, Australia, Tuvalu, Antarctica, the Arctic and the great mountains of the world, documenting climate science and the effects of change," his website said.

"This work continues into its second decade, with new emphasis on re-photographing rapid changes and on the solutions which will reduce greenhouse gas emissions."

The Australian Museum and Lizard Island Research Station extended its sympathies to Mr Braasch's family and friends.